System and method for providing sub-band whitening in the presence of partial-band interference

ABSTRACT

A method and system for providing sub-band whitening are herein provided. According to one embodiment, a method estimating an interference whitening (IW) factor based on a legacy-long training field (LLTF) signal, updating the estimated IW factor during transmission of a data symbol, and scaling the data symbol based on the updated IW factor and the estimated IW factor.

PRIORITY

This application is a Continuation of U.S. patent application Ser. No.16/664,237, filed on Oct. 25, 2019 and scheduled to issue as U.S. Pat.No. 10,911,096 on Feb. 2, 2021, which is based on and claims priorityunder 35 U.S.C. § 119(e) to U.S. Provisional Patent Application filed onAug. 7, 2019 in the United States Patent and Trademark Office andassigned Ser. No. 62/883,862, the entire contents of which areincorporated herein by reference.

FIELD

The present disclosure is generally related to wireless communicationsystems. In particular, the present disclosure is related to a systemand method for providing sub-band whitening in the presence ofpartial-band interference.

BACKGROUND

In Wi-Fi communication systems, due to a contention based transmissionopportunity, interference may be strong for some packets. In theInstitute of Electrical and Electronics Engineers (IEEE) 802.11 acstandard and IEEE 802.11 ax standard, the transmitting bandwidth may be80 megahertz (MHz) and 160 MHz. In a case of overlapping basic serviceset (BSS) (OBSS), partial-band interference may be present for wide-band(e.g., 40/80/160 MHz) that affects one or more of the available 20 MHzsub-bands and thus may cause severe performance degradation.

SUMMARY

According to one embodiment, a method includes estimating aninterference whitening (IW) factor based on a legacy-long training field(LLTF) signal, updating the estimated IW factor during transmission of adata symbol, and scaling the data symbol based on the updated IW factorand the estimated IW factor.

According to one embodiment, a system includes a transceiver, a memoryand a processor configured to estimate an interference whitening (IW)factor based on a legacy-long training field (LLTF) signal, update theestimated IW factor during transmission of a data symbol, and scale thedata symbol based on the updated IW factor and the estimated IW factor.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present disclosure will be more apparent from thefollowing detailed description, taken in conjunction with theaccompanying drawings, in which:

FIG. 1 illustrates a diagram of a signal structure including aninterference signal, according to an embodiment;

FIG. 2A illustrates a diagram of a system for providing sub-bandwhitening in the presence of partial-band interference, according to anembodiment;

FIG. 2B illustrates a diagram of a system for providing sub-bandwhitening in the presence of partial-band interference, according to anembodiment;

FIG. 3 illustrates a flowchart of a method for providing sub-bandwhitening in the presence of partial-band interference, according to anembodiment;

FIG. 4 illustrates a diagram of a system for estimation of noise andinterference power (NIVar) in a time domain, according to an embodiment;

FIG. 5 illustrates a diagram of a system for estimation of NIVar in afrequency domain, according to an embodiment;

FIG. 6 illustrates a diagram of a system for NIVar estimation from data,according to an embodiment; and

FIG. 7 illustrates a block diagram of an electronic device in a networkenvironment, according to one embodiment.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure are described indetail with reference to the accompanying drawings. It should be notedthat the same elements will be designated by the same reference numeralsalthough they are shown in different drawings. In the followingdescription, specific details such as detailed configurations andcomponents are merely provided to assist with the overall understandingof the embodiments of the present disclosure. Therefore, it should beapparent to those skilled in the art that various changes andmodifications of the embodiments described herein may be made withoutdeparting from the scope of the present disclosure. In addition,descriptions of well-known functions and constructions are omitted forclarity and conciseness. The terms described below are terms defined inconsideration of the functions in the present disclosure, and may bedifferent according to users, intentions of the users, or customs.Therefore, the definitions of the terms should be determined based onthe contents throughout this specification.

The present disclosure may have various modifications and variousembodiments, among which embodiments are described below in detail withreference to the accompanying drawings. However, it should be understoodthat the present disclosure is not limited to the embodiments, butincludes all modifications, equivalents, and alternatives within thescope of the present disclosure.

Although the terms including an ordinal number such as first, second,etc. may be used for describing various elements, the structuralelements are not restricted by the terms. The terms are only used todistinguish one element from another element. For example, withoutdeparting from the scope of the present disclosure, a first structuralelement may be referred to as a second structural element. Similarly,the second structural element may also be referred to as the firststructural element. As used herein, the term “and/or” includes any andall combinations of one or more associated items.

The terms used herein are merely used to describe various embodiments ofthe present disclosure but are not intended to limit the presentdisclosure. Singular forms are intended to include plural forms unlessthe context clearly indicates otherwise. In the present disclosure, itshould be understood that the terms “include” or “have” indicateexistence of a feature, a number, a step, an operation, a structuralelement, parts, or a combination thereof, and do not exclude theexistence or probability of the addition of one or more other features,numerals, steps, operations, structural elements, parts, or combinationsthereof.

Unless defined differently, all terms used herein have the same meaningsas those understood by a person skilled in the art to which the presentdisclosure belongs. Terms such as those defined in a generally useddictionary are to be interpreted to have the same meanings as thecontextual meanings in the relevant field of art, and are not to beinterpreted to have ideal or excessively formal meanings unless clearlydefined in the present disclosure.

The electronic device according to one embodiment may be one of varioustypes of electronic devices. The electronic devices may include, forexample, a portable communication device (e.g. a smart phone), acomputer, a portable multimedia device, a portable medical device, acamera, a wearable device, or a home appliance. According to oneembodiment of the disclosure, an electronic device is not limited tothose described above.

The terms used in the present disclosure are not intended to limit thepresent disclosure but are intended to include various changes,equivalents, or replacements for a corresponding embodiment. With regardto the descriptions of the accompanying drawings, similar referencenumerals may be used to refer to similar or related elements. A singularform of a noun corresponding to an item may include one or more of thethings, unless the relevant context clearly indicates otherwise. As usedherein, each of such phrases as “A or B,” “at least one of A and B,” “atleast one of A or B,” “A, B, or C,” “at least one of A, B, and C,” and“at least one of A, B, or C,” may include all possible combinations ofthe items enumerated together in a corresponding one of the phrases. Asused herein, terms such as “1^(st),” “2nd,” “first,” and “second” may beused to distinguish a corresponding component from another component,but are not intended to limit the components in other aspects (e.g.,importance or order). It is intended that if an element (e.g., a firstelement) is referred to, with or without the term “operatively” or“communicatively”, as “coupled with,” “coupled to,” “connected with,” or“connected to” another element (e.g., a second element), it indicatesthat the element may be coupled with the other element directly (e.g.,wired), wirelessly, or via a third element.

As used herein, the term “module” may include a unit implemented inhardware, software, or firmware, and may interchangeably be used withother terms, for example, “logic,” “logic block,” “part,” and“circuitry.” A module may be a single integral component, or a minimumunit or part thereof, adapted to perform one or more functions. Forexample, according to one embodiment, a module may be implemented in aform of an application-specific integrated circuit (ASIC).

FIG. 1 illustrates a diagram of a signal structure including aninterference signal, according to an embodiment. As depicted, the datapacket 102 may include data sub-bands 104, 106, 108 and 110. As shown,an interference signal 112 is interfering with data sub-band 104, andthe interference signal 112 can start and end at any part of the datapacket 102.

To mitigate degradation of the signals due to partial-band interference,the present system and method provides a frequency-domain-based signalwhitening (scaling) according to the estimated interference whitening(IW) factor based on an estimated noise and interference variance(NIVar) (e.g., per 20-MHz-sub-band).

A Wi-Fi packet may be divided into two parts, a preamble part and a datapart. The preamble part begins with a legacy-long training field (LLTF)that provides estimations. The data part comes after the preamble part.

FIG. 2A illustrates a diagram of a system for providing sub-bandwhitening in the presence of partial-band interference, according to anembodiment. A system 200 receives an initial signal y(i, n) forprocessing at the estimation of a NIVar block 202. The initial signalmay be in the time domain or the frequency domain. The system includes aNIVar estimation from LLTF block 204 and a NIVar estimation from datablock 206, the details of which will be described with reference toFIGS. 3-6. The system also processes the initial signal y(i, n) througha frequency and timing correction block 208 to correct for carrierfrequency offset and provides, at the block output, the received signalstarting from the first sample of a valid detected WiFi preamble. Then,the cyclic prefix (CP) for each OFDM symbol is discarded through a CPremoval block 210. A FFT block 212 is used to obtain thefrequency-domain signal for each OFDM symbol. The system 200 alsoincludes a channel estimation block 214 to obtain an estimate for thechannel experienced by the received signal. In addition, a symboldetector 216 is used to obtain an estimate for the log-likelihood ratios(LLRs) of the available bits per data symbol. Then, a hard decisionblock 218 decides whether each LLR corresponds to a zero-valued bit or aone-valued bit. The bits obtained from the hard decision block are fedto a symbol mapper 220 to regenerate estimates for the transmitted datasymbols to be used for noise and interference power estimation duringthe data part reception. A mixer 215 scales the data symbols output bythe FFT block 212 and a mixer 217 scales the channel output from thechannel estimation block 214. The system 200 processes the output of theNIVar estimation from LLTF block 204 and the output of the NIVarestimation from data block 206 where both outputs are fed to the NIVarestimate combiner block 221 followed by a per-sub-band scalingcomputation block 222 that performs the task of updating the IW factorusing the NIVar estimates obtained from L-LTF and from data through theuse of a first-order low-pass filter to smooth out the estimates overtime.

FIG. 2B illustrates a diagram of a system for providing sub-bandwhitening in the presence of partial-band interference, according to anembodiment. A system 250 receives the initial signal y(i, n) forprocessing at the estimation of a NIVar estimation block 252. Theinitial signal may be in the time domain or the frequency domain. Thesystem 250 includes a NIVar estimation from LLTF block 254 and a NIVarestimation from data block 256, the details of which will be describedwith reference to FIGS. 3-6. The system 250 also processes the initialsignal y(i, n) through a frequency and timing correction block 258, acyclic prefix (CP) removal block 260, and an FFT block 262. The system250 also includes a channel estimation block 264, a symbol detector 266,a hard decision block 268, and a symbol mapper 270. The mixer 263 scalesthe data symbols output by the FFT block 262. In the embodiment shown inFIG. 2B, the data symbols are scaled at the output of the FFT block 262and no scaling of the channel is necessary. The system 250 processes theoutput of the NIVar estimation from LLTF block 254 and the output of theNIVar estimation from data block 256 where both outputs are fed to aNIVar estimate combiner block 271 followed by a per-sub-band scalingcomputation block 272 which also utilizes the scaled data symbols scaledat the mixer 263.

FIG. 3 illustrates a flowchart 300 of a method for providing sub-bandwhitening in the presence of partial-band interference, according to anembodiment. At 302, the present system estimates an IW factor based onan LLTF symbol. The system estimates an 1 W factor based on NIVarestimation at LLTF symbols.

FIG. 4 illustrates a diagram of a system for estimation of NIVar in atime domain An input wide-band signal is split into four 20 MHz signals402 a, 402 b, 402 c, and 402 d where the signal in each 20 MHz sub-bandis frequency-translated into baseband via mixers 403 a, 403 b, 403 c,and 403 d and then low-pass filtered (LPF) at 404 a, 404 b, 404 c, and404 d, respectively. For 40/80 MHz BSS bandwidths, either two or fourbranches may be considered for further processing, respectively,depending on the bandwidth detection output. Following the LPFs, thesignals 402 a, 402 b, 402 c, and 402 d are decimated at 405 a, 405 b,405 c, and 405 d, respectively, (down-sampled) by a factor of 2 or 4 for40 or 80 MHz bandwidths, respectively. It is appreciated that thewide-band signal may be split into signals with other bandwidths withoutdeviating from the scope of the present disclosure. The system estimatesthe NIVar per sub-band, at the output of a band selection block 410, byprocessing the split sub-band signals in sequence. The NIVar persub-band is estimated from the two LLTF identical segments and thesystem outputs an IW factor estimation 412.

FIG. 5 illustrates a diagram of a system for estimation of NIVar in afrequency domain, according to an embodiment. The system 500 receivesthe time domain signal, performs an FFT operation at 502, and splits itinto four 20 MHz signals 504 a, 504 b, 504 c, and 504 d and the signalsare decimated at 506 a, 506 b, 506 c, and 506 d, respectively. The LPFfunction of FIG. 4 is not needed in the system 500. In this case,sub-band position is easily known for LLTF frequency-domain sequences.It is noted that the interference power may change during the packettransmission since an interfering packet arrival time and time span arerandom. Hence, the NIVar and hence the IW factor are updated and thensmoothed through filtering during the packet transmission on anorthogonal frequency division multiplexing (OFDM)-block basis. Thesystem estimates the NIVar per sub-band, at a band-selection block 512,by processing the split sub-band signals in sequence. The NIVar persub-band is estimated from the two LLTF identical segments and thesystem outputs an IW factor estimation 514.

At 304, the present system updates the estimated IW factor duringtransmission of a data symbol. FIG. 6 illustrates a diagram of a system600 for NIVar estimation from data, according to an embodiment. Thesystem 600 includes a hard decision block 604, a modulation block 608, amagnitude square operation block 620, and a summation operation block622. The system 600 utilizes three input quantities the LLR(k)s for acertain data symbol 602, the channel estimation Ĥ(i, k) 612 and thefrequency-domain received signal Y(i, k) 616. The channel estimation 612is scaled at mixer 613, and the frequency-domain received signal 616 andthe scaled channel estimation are summed at accumulator 615.

The frequency-domain received signal for the i-th symbol is defined asEquation (1):

Y(i,k)=Σ_(spatial streams) H(k)X(i,k)+I(i,k)+N(i,k),  (1)

where k is the subcarrier index, I(i, k) is the interference, and N(i,k) is the noise. For each symbol, after symbol detection, thetransmitted symbol can be regenerated based on the LLR 602 via the harddecision block 604 and the modulation block 608, which produces theregenerated symbol as {circumflex over (X)}(i, k) 610. The noise andinterference for this subcarrier can be estimated as Equation (2).

$\begin{matrix}{{{NI}\left( {i,k} \right)} = {{Y\left( {i,k} \right)} - {\sum\limits_{{spatial}\mspace{14mu}{streams}}{{\hat{H}\left( {i,k} \right)}{{\hat{X}\left( {i,k} \right)}.}}}}} & (2)\end{matrix}$

Assuming the interference and noise are zero mean, the noiseinterference power variance for each sub-band (20 MHz) can be estimatedas Equation (3):

$\begin{matrix}{{{\hat{\sigma}}_{i,j}^{2} = \frac{\sum_{k \in {{subband}\mspace{14mu} i{{{NI}{({i,k})}}}^{2}}}}{N_{j}}},} & (3)\end{matrix}$

where {circumflex over (σ)}_(i,j) ² 624 (produced using the magnitudesquare operation block 620 and the summation operation block 622 asshown in Equation (3)) is the error vector magnitude (EVM) of the i-thsymbol on j-th sub-band, and N_(j) is the number of subcarriers in thej-th sub-band.

Referring back to FIG. 3, at 306, the present system scales the channeland/or the data symbol based on the estimated IW factor and the updatedIW factor. Using the estimated noise-plus-interference power persub-band, the frequency domain signal per sub-band may be scaledaccording to Equation (4):

{tilde over (Y)}(i,k)=Y(i,k)*S(i,j _(k))  (4)

where {tilde over (Y)}(i,k) is the frequency domain signal afterscaling, S(i, j_(k)) is the IW factor at the i-th symbol, and j_(k)-thsub-band (j_(k) means that k-th subcarrier is in the j_(k)-th sub-band).The frequency domain signal per sub-band may also be scaled according toEquation (5):

$\begin{matrix}{{{S\left( {i,j} \right)} = \sqrt{\frac{1/{\hat{\sigma}}_{i,j}^{2}}{{1/N_{d}}{\sum_{m = 1}^{N_{d}}{1/{\hat{\sigma}}_{i,m}^{2}}}}}},\mspace{14mu}{j = 1},\ldots\mspace{14mu},N_{d}} & (5)\end{matrix}$

where S(i,j) is the scaling factor for the subcarriers that belong tothe i-th symbol j-th sub-band, {circumflex over (σ)}_(i,j) ² is theestimated NIVar on the j-th sub-band, and N_(d) is the number ofdetected sub-bands.

The scaling factors may be normalized over the maximum scaling factor asan alternative to normalizing over the average of the scaling factors.Hence, the scaling factors can be rewritten as Equation (6).

$\begin{matrix}{{{S\left( {i,j} \right)} = \frac{1/{\hat{\sigma}}_{i,j}}{\max\limits_{j}{1/{\hat{\sigma}}_{i,j}}}},\mspace{14mu}{j = 1},\ldots\mspace{14mu},N_{d},} & (6)\end{matrix}$

Normalization by the maximum value sets the maximum of the resultantnormalized factors to 1 and does not change the dynamic range of thedata as might happen if it is chosen to normalize by the average value.

FIG. 7 illustrates a block diagram of an electronic device 701 in anetwork environment 700, according to one embodiment. Referring to FIG.7, the electronic device 701 in the network environment 700 maycommunicate with an electronic device 702 via a first network 798 (e.g.,a short-range wireless communication network), or an electronic device704 or a server 708 via a second network 799 (e.g., a long-rangewireless communication network). The electronic device 701 maycommunicate with the electronic device 704 via the server 708. Theelectronic device 701 may include a processor 720, a memory 730, aninput device 750, a sound output device 755, a display device 760, anaudio module 770, a sensor module 776, an interface 777, a haptic module779, a camera module 780, a power management module 788, a battery 789,a communication module 790, a subscriber identification module (SIM)796, or an antenna module 797. In one embodiment, at least one (e.g.,the display device 760 or the camera module 780) of the components maybe omitted from the electronic device 701, or one or more othercomponents may be added to the electronic device 701. In one embodiment,some of the components may be implemented as a single integrated circuit(IC). For example, the sensor module 776 (e.g., a fingerprint sensor, aniris sensor, or an illuminance sensor) may be embedded in the displaydevice 760 (e.g., a display).

The processor 720 may execute, for example, software (e.g., a program740) to control at least one other component (e.g., a hardware or asoftware component) of the electronic device 701 coupled with theprocessor 720, and may perform various data processing or computations.As at least part of the data processing or computations, the processor720 may load a command or data received from another component (e.g.,the sensor module 776 or the communication module 790) in volatilememory 732, process the command or the data stored in the volatilememory 732, and store resulting data in non-volatile memory 734. Theprocessor 720 may include a main processor 721 (e.g., a centralprocessing unit (CPU) or an application processor (AP)), and anauxiliary processor 723 (e.g., a graphics processing unit (GPU), animage signal processor (ISP), a sensor hub processor, or a communicationprocessor (CP)) that is operable independently from, or in conjunctionwith, the main processor 721. Additionally or alternatively, theauxiliary processor 723 may be adapted to consume less power than themain processor 721, or execute a particular function. The auxiliaryprocessor 723 may be implemented as being separate from, or a part of,the main processor 721.

The auxiliary processor 723 may control at least some of the functionsor states related to at least one component (e.g., the display device760, the sensor module 776, or the communication module 790) among thecomponents of the electronic device 701, instead of the main processor721 while the main processor 721 is in an inactive (e.g., sleep) state,or together with the main processor 721 while the main processor 721 isin an active state (e.g., executing an application). According to oneembodiment, the auxiliary processor 723 (e.g., an image signal processoror a communication processor) may be implemented as part of anothercomponent (e.g., the camera module 780 or the communication module 790)functionally related to the auxiliary processor 723.

The memory 730 may store various data used by at least one component(e.g., the processor 720 or the sensor module 776) of the electronicdevice 701. The various data may include, for example, software (e.g.,the program 740) and input data or output data for a command relatedthereto. The memory 730 may include the volatile memory 732 or thenon-volatile memory 734.

The program 740 may be stored in the memory 730 as software, and mayinclude, for example, an operating system (OS) 742, middleware 744, oran application 746.

The input device 750 may receive a command or data to be used by othercomponent (e.g., the processor 720) of the electronic device 701, fromthe outside (e.g., a user) of the electronic device 701. The inputdevice 750 may include, for example, a microphone, a mouse, or akeyboard.

The sound output device 755 may output sound signals to the outside ofthe electronic device 701. The sound output device 755 may include, forexample, a speaker or a receiver. The speaker may be used for generalpurposes, such as playing multimedia or recording, and the receiver maybe used for receiving an incoming call. According to one embodiment, thereceiver may be implemented as being separate from, or a part of, thespeaker.

The display device 760 may visually provide information to the outside(e.g., a user) of the electronic device 701. The display device 760 mayinclude, for example, a display, a hologram device, or a projector andcontrol circuitry to control a corresponding one of the display,hologram device, and projector. According to one embodiment, the displaydevice 760 may include touch circuitry adapted to detect a touch, orsensor circuitry (e.g., a pressure sensor) adapted to measure theintensity of force incurred by the touch.

The audio module 770 may convert a sound into an electrical signal andvice versa. According to one embodiment, the audio module 770 may obtainthe sound via the input device 750, or output the sound via the soundoutput device 755 or a headphone of an external electronic device 702directly (e.g., wired) or wirelessly coupled with the electronic device701.

The sensor module 776 may detect an operational state (e.g., power ortemperature) of the electronic device 701 or an environmental state(e.g., a state of a user) external to the electronic device 701, andthen generate an electrical signal or data value corresponding to thedetected state. The sensor module 776 may include, for example, agesture sensor, a gyro sensor, an atmospheric pressure sensor, amagnetic sensor, an acceleration sensor, a grip sensor, a proximitysensor, a color sensor, an infrared (IR) sensor, a biometric sensor, atemperature sensor, a humidity sensor, or an illuminance sensor.

The interface 777 may support one or more specified protocols to be usedfor the electronic device 701 to be coupled with the external electronicdevice 702 directly (e.g., wired) or wirelessly. According to oneembodiment, the interface 777 may include, for example, a highdefinition multimedia interface (HDMI), a universal serial bus (USB)interface, a secure digital (SD) card interface, or an audio interface.

A connecting terminal 778 may include a connector via which theelectronic device 701 may be physically connected with the externalelectronic device 702. According to one embodiment, the connectingterminal 778 may include, for example, an HDMI connector, a USBconnector, an SD card connector, or an audio connector (e.g., aheadphone connector).

The haptic module 779 may convert an electrical signal into a mechanicalstimulus (e.g., a vibration or a movement) or an electrical stimuluswhich may be recognized by a user via tactile sensation or kinestheticsensation. According to one embodiment, the haptic module 779 mayinclude, for example, a motor, a piezoelectric element, or an electricalstimulator.

The camera module 780 may capture a still image or moving images.According to one embodiment, the camera module 780 may include one ormore lenses, image sensors, image signal processors, or flashes.

The power management module 788 may manage power supplied to theelectronic device 701. The power management module 788 may beimplemented as at least part of, for example, a power managementintegrated circuit (PMIC).

The battery 789 may supply power to at least one component of theelectronic device 701. According to one embodiment, the battery 789 mayinclude, for example, a primary cell which is not rechargeable, asecondary cell which is rechargeable, or a fuel cell.

The communication module 790 may support establishing a direct (e.g.,wired) communication channel or a wireless communication channel betweenthe electronic device 701 and the external electronic device (e.g., theelectronic device 702, the electronic device 704, or the server 708) andperforming communication via the established communication channel. Thecommunication module 790 may include one or more communicationprocessors that are operable independently from the processor 720 (e.g.,the AP) and supports a direct (e.g., wired) communication or a wirelesscommunication. According to one embodiment, the communication module 790may include a wireless communication module 792 (e.g., a cellularcommunication module, a short-range wireless communication module, or aglobal navigation satellite system (GNSS) communication module) or awired communication module 794 (e.g., a local area network (LAN)communication module or a power line communication (PLC) module). Acorresponding one of these communication modules may communicate withthe external electronic device via the first network 798 (e.g., ashort-range communication network, such as Bluetooth™, wireless-fidelity(Wi-Fi) direct, or a standard of the Infrared Data Association (IrDA))or the second network 799 (e.g., a long-range communication network,such as a cellular network, the Internet, or a computer network (e.g.,LAN or wide area network (WAN)). These various types of communicationmodules may be implemented as a single component (e.g., a single IC), ormay be implemented as multiple components (e.g., multiple ICs) that areseparate from each other. The wireless communication module 792 mayidentify and authenticate the electronic device 701 in a communicationnetwork, such as the first network 798 or the second network 799, usingsubscriber information (e.g., international mobile subscriber identity(IMSI)) stored in the subscriber identification module 796.

The antenna module 797 may transmit or receive a signal or power to orfrom the outside (e.g., the external electronic device) of theelectronic device 701. According to one embodiment, the antenna module797 may include one or more antennas, and, therefrom, at least oneantenna appropriate for a communication scheme used in the communicationnetwork, such as the first network 798 or the second network 799, may beselected, for example, by the communication module 790 (e.g., thewireless communication module 792). The signal or the power may then betransmitted or received between the communication module 790 and theexternal electronic device via the selected at least one antenna.

At least some of the above-described components may be mutually coupledand communicate signals (e.g., commands or data) therebetween via aninter-peripheral communication scheme (e.g., a bus, a general purposeinput and output (GPIO), a serial peripheral interface (SPI), or amobile industry processor interface (MIPI)).

According to one embodiment, commands or data may be transmitted orreceived between the electronic device 701 and the external electronicdevice 704 via the server 708 coupled with the second network 799. Eachof the electronic devices 702 and 704 may be a device of a same type as,or a different type, from the electronic device 701. All or some ofoperations to be executed at the electronic device 701 may be executedat one or more of the external electronic devices 702, 704, or 708. Forexample, if the electronic device 701 should perform a function or aservice automatically, or in response to a request from a user oranother device, the electronic device 701, instead of, or in additionto, executing the function or the service, may request the one or moreexternal electronic devices to perform at least part of the function orthe service. The one or more external electronic devices receiving therequest may perform the at least part of the function or the servicerequested, or an additional function or an additional service related tothe request, and transfer an outcome of the performing to the electronicdevice 701. The electronic device 701 may provide the outcome, with orwithout further processing of the outcome, as at least part of a replyto the request. To that end, a cloud computing, distributed computing,or client-server computing technology may be used, for example.

One embodiment may be implemented as software (e.g., the program 740)including one or more instructions that are stored in a storage medium(e.g., internal memory 736 or external memory 738) that is readable by amachine (e.g., the electronic device 701). For example, a processor ofthe electronic device 701 may invoke at least one of the one or moreinstructions stored in the storage medium, and execute it, with orwithout using one or more other components under the control of theprocessor. Thus, a machine may be operated to perform at least onefunction according to the at least one instruction invoked. The one ormore instructions may include code generated by a complier or codeexecutable by an interpreter. A machine-readable storage medium may beprovided in the form of a non-transitory storage medium. The term“non-transitory” indicates that the storage medium is a tangible device,and does not include a signal (e.g., an electromagnetic wave), but thisterm does not differentiate between where data is semi-permanentlystored in the storage medium and where the data is temporarily stored inthe storage medium.

According to one embodiment, a method of the disclosure may be includedand provided in a computer program product. The computer program productmay be traded as a product between a seller and a buyer. The computerprogram product may be distributed in the form of a machine-readablestorage medium (e.g., a compact disc read only memory (CD-ROM)), or bedistributed (e.g., downloaded or uploaded) online via an applicationstore (e.g., Play Store™), or between two user devices (e.g., smartphones) directly. If distributed online, at least part of the computerprogram product may be temporarily generated or at least temporarilystored in the machine-readable storage medium, such as memory of themanufacturer's server, a server of the application store, or a relayserver.

According to one embodiment, each component (e.g., a module or aprogram) of the above-described components may include a single entityor multiple entities. One or more of the above-described components maybe omitted, or one or more other components may be added. Alternativelyor additionally, a plurality of components (e.g., modules or programs)may be integrated into a single component. In this case, the integratedcomponent may still perform one or more functions of each of theplurality of components in the same or similar manner as they areperformed by a corresponding one of the plurality of components beforethe integration. Operations performed by the module, the program, oranother component may be carried out sequentially, in parallel,repeatedly, or heuristically, or one or more of the operations may beexecuted in a different order or omitted, or one or more otheroperations may be added.

Although certain embodiments of the present disclosure have beendescribed in the detailed description of the present disclosure, thepresent disclosure may be modified in various forms without departingfrom the scope of the present disclosure. Thus, the scope of the presentdisclosure shall not be determined merely based on the describedembodiments, but rather determined based on the accompanying claims andequivalents thereto.

What is claimed is:
 1. A method for providing sub-band whitening,comprising: deriving an interference whitening (IW) factor, an estimatednoise plus interference variance (NIVar), and a legacy-long trainingfield (LLTF) signal; scaling a frequency domain signal for a sub-bandusing the IW factor; and updating the IW factor by using a sub-bandNIVar.
 2. The method of claim 1, wherein the IW factor is updated basedon an NIVar of a received signal and a symbol detection output.
 3. Themethod of claim 1, wherein the estimated NIVar is estimated based on areceived signal and a data detection result.
 4. The method of claim 1,wherein the IW factor is updated by using a sub-band NIVar at each of anumber of data symbols.
 5. The method of claim 1, further comprisingscaling a channel, wherein scaling the channel is performed based on anormalization of scaling factors.
 6. The method of claim 1, furthercomprising splitting the LLTF signal into multiple signals.
 7. Themethod of claim 1, wherein the LLTF signal is split into four signals.8. The method of claim 7, wherein each of the four signals are in a 20MHz sub-band.
 9. The method of claim 1, wherein estimating the IW factorincludes determining an error vector magnitude (EVM).
 10. The method ofclaim 9, wherein the EVM is determined based on a channel estimation anda data signal.
 11. A system for providing sub-band whitening,comprising: a transceiver; a memory; and a processor configured to:derive an interference whitening (IW) factor, an estimated noise plusinterference variance (NIVar), and a legacy-long training field (LLTF)signal; scale a frequency domain signal for a sub-band using the IWfactor; and update the IW factor by using a sub-band NIVar.
 12. Thesystem of claim 11, wherein the IW factor is updated based on an NIVarof a received signal and a symbol detection output.
 13. The system ofclaim 11, wherein the estimated NIVar is estimated based on a receivedsignal and a data detection result.
 14. The system of claim 11, whereinthe IW factor is updated by using a sub-band NIVar at each of a numberof data symbols.
 15. The system of claim 11, wherein the processor isfurther configured to scale a channel based on a normalization ofscaling factors.
 16. The system of claim 11, wherein the processor isfurther configured to split the LLTF signal into multiple signals. 17.The system of claim 11, wherein the LLTF signal is split into foursignals.
 18. The system of claim 17, wherein each of the four signalsare in a 20 MHz sub-band.
 19. The system of claim 11, wherein theprocessor is further configured to estimate the IW factor by determiningan error vector magnitude (EVM).
 20. The system of claim 19, wherein theEVM is determined based on a channel estimation and a data signal.